1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * self test for change_page_attr.
4 *
5 * Clears the a test pte bit on random pages in the direct mapping,
6 * then reverts and compares page tables forwards and afterwards.
7 */
8 #include <linux/bootmem.h>
9 #include <linux/kthread.h>
10 #include <linux/random.h>
11 #include <linux/kernel.h>
12 #include <linux/init.h>
13 #include <linux/mm.h>
14 #include <linux/vmalloc.h>
15
16 #include <asm/cacheflush.h>
17 #include <asm/pgtable.h>
18 #include <asm/kdebug.h>
19
20 /*
21 * Only print the results of the first pass:
22 */
23 static __read_mostly int print = 1;
24
25 enum {
26 NTEST = 400,
27 #ifdef CONFIG_X86_64
28 LPS = (1 << PMD_SHIFT),
29 #elif defined(CONFIG_X86_PAE)
30 LPS = (1 << PMD_SHIFT),
31 #else
32 LPS = (1 << 22),
33 #endif
34 GPS = (1<<30)
35 };
36
37 #define PAGE_CPA_TEST __pgprot(_PAGE_CPA_TEST)
38
pte_testbit(pte_t pte)39 static int pte_testbit(pte_t pte)
40 {
41 return pte_flags(pte) & _PAGE_SOFTW1;
42 }
43
44 struct split_state {
45 long lpg, gpg, spg, exec;
46 long min_exec, max_exec;
47 };
48
print_split(struct split_state * s)49 static int print_split(struct split_state *s)
50 {
51 long i, expected, missed = 0;
52 int err = 0;
53
54 s->lpg = s->gpg = s->spg = s->exec = 0;
55 s->min_exec = ~0UL;
56 s->max_exec = 0;
57 for (i = 0; i < max_pfn_mapped; ) {
58 unsigned long addr = (unsigned long)__va(i << PAGE_SHIFT);
59 unsigned int level;
60 pte_t *pte;
61
62 pte = lookup_address(addr, &level);
63 if (!pte) {
64 missed++;
65 i++;
66 continue;
67 }
68
69 if (level == PG_LEVEL_1G && sizeof(long) == 8) {
70 s->gpg++;
71 i += GPS/PAGE_SIZE;
72 } else if (level == PG_LEVEL_2M) {
73 if ((pte_val(*pte) & _PAGE_PRESENT) && !(pte_val(*pte) & _PAGE_PSE)) {
74 printk(KERN_ERR
75 "%lx level %d but not PSE %Lx\n",
76 addr, level, (u64)pte_val(*pte));
77 err = 1;
78 }
79 s->lpg++;
80 i += LPS/PAGE_SIZE;
81 } else {
82 s->spg++;
83 i++;
84 }
85 if (!(pte_val(*pte) & _PAGE_NX)) {
86 s->exec++;
87 if (addr < s->min_exec)
88 s->min_exec = addr;
89 if (addr > s->max_exec)
90 s->max_exec = addr;
91 }
92 }
93 if (print) {
94 printk(KERN_INFO
95 " 4k %lu large %lu gb %lu x %lu[%lx-%lx] miss %lu\n",
96 s->spg, s->lpg, s->gpg, s->exec,
97 s->min_exec != ~0UL ? s->min_exec : 0,
98 s->max_exec, missed);
99 }
100
101 expected = (s->gpg*GPS + s->lpg*LPS)/PAGE_SIZE + s->spg + missed;
102 if (expected != i) {
103 printk(KERN_ERR "CPA max_pfn_mapped %lu but expected %lu\n",
104 max_pfn_mapped, expected);
105 return 1;
106 }
107 return err;
108 }
109
110 static unsigned long addr[NTEST];
111 static unsigned int len[NTEST];
112
113 /* Change the global bit on random pages in the direct mapping */
pageattr_test(void)114 static int pageattr_test(void)
115 {
116 struct split_state sa, sb, sc;
117 unsigned long *bm;
118 pte_t *pte, pte0;
119 int failed = 0;
120 unsigned int level;
121 int i, k;
122 int err;
123 unsigned long test_addr;
124
125 if (print)
126 printk(KERN_INFO "CPA self-test:\n");
127
128 bm = vzalloc((max_pfn_mapped + 7) / 8);
129 if (!bm) {
130 printk(KERN_ERR "CPA Cannot vmalloc bitmap\n");
131 return -ENOMEM;
132 }
133
134 failed += print_split(&sa);
135
136 for (i = 0; i < NTEST; i++) {
137 unsigned long pfn = prandom_u32() % max_pfn_mapped;
138
139 addr[i] = (unsigned long)__va(pfn << PAGE_SHIFT);
140 len[i] = prandom_u32() % 100;
141 len[i] = min_t(unsigned long, len[i], max_pfn_mapped - pfn - 1);
142
143 if (len[i] == 0)
144 len[i] = 1;
145
146 pte = NULL;
147 pte0 = pfn_pte(0, __pgprot(0)); /* shut gcc up */
148
149 for (k = 0; k < len[i]; k++) {
150 pte = lookup_address(addr[i] + k*PAGE_SIZE, &level);
151 if (!pte || pgprot_val(pte_pgprot(*pte)) == 0 ||
152 !(pte_val(*pte) & _PAGE_PRESENT)) {
153 addr[i] = 0;
154 break;
155 }
156 if (k == 0) {
157 pte0 = *pte;
158 } else {
159 if (pgprot_val(pte_pgprot(*pte)) !=
160 pgprot_val(pte_pgprot(pte0))) {
161 len[i] = k;
162 break;
163 }
164 }
165 if (test_bit(pfn + k, bm)) {
166 len[i] = k;
167 break;
168 }
169 __set_bit(pfn + k, bm);
170 }
171 if (!addr[i] || !pte || !k) {
172 addr[i] = 0;
173 continue;
174 }
175
176 test_addr = addr[i];
177 err = change_page_attr_set(&test_addr, len[i], PAGE_CPA_TEST, 0);
178 if (err < 0) {
179 printk(KERN_ERR "CPA %d failed %d\n", i, err);
180 failed++;
181 }
182
183 pte = lookup_address(addr[i], &level);
184 if (!pte || !pte_testbit(*pte) || pte_huge(*pte)) {
185 printk(KERN_ERR "CPA %lx: bad pte %Lx\n", addr[i],
186 pte ? (u64)pte_val(*pte) : 0ULL);
187 failed++;
188 }
189 if (level != PG_LEVEL_4K) {
190 printk(KERN_ERR "CPA %lx: unexpected level %d\n",
191 addr[i], level);
192 failed++;
193 }
194
195 }
196 vfree(bm);
197
198 failed += print_split(&sb);
199
200 for (i = 0; i < NTEST; i++) {
201 if (!addr[i])
202 continue;
203 pte = lookup_address(addr[i], &level);
204 if (!pte) {
205 printk(KERN_ERR "CPA lookup of %lx failed\n", addr[i]);
206 failed++;
207 continue;
208 }
209 test_addr = addr[i];
210 err = change_page_attr_clear(&test_addr, len[i], PAGE_CPA_TEST, 0);
211 if (err < 0) {
212 printk(KERN_ERR "CPA reverting failed: %d\n", err);
213 failed++;
214 }
215 pte = lookup_address(addr[i], &level);
216 if (!pte || pte_testbit(*pte)) {
217 printk(KERN_ERR "CPA %lx: bad pte after revert %Lx\n",
218 addr[i], pte ? (u64)pte_val(*pte) : 0ULL);
219 failed++;
220 }
221
222 }
223
224 failed += print_split(&sc);
225
226 if (failed) {
227 WARN(1, KERN_ERR "NOT PASSED. Please report.\n");
228 return -EINVAL;
229 } else {
230 if (print)
231 printk(KERN_INFO "ok.\n");
232 }
233
234 return 0;
235 }
236
do_pageattr_test(void * __unused)237 static int do_pageattr_test(void *__unused)
238 {
239 while (!kthread_should_stop()) {
240 schedule_timeout_interruptible(HZ*30);
241 if (pageattr_test() < 0)
242 break;
243 if (print)
244 print--;
245 }
246 return 0;
247 }
248
start_pageattr_test(void)249 static int start_pageattr_test(void)
250 {
251 struct task_struct *p;
252
253 p = kthread_create(do_pageattr_test, NULL, "pageattr-test");
254 if (!IS_ERR(p))
255 wake_up_process(p);
256 else
257 WARN_ON(1);
258
259 return 0;
260 }
261 device_initcall(start_pageattr_test);
262